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Light can rescue auxin-dependent synchrony of cell division in a tobacco cell line.

Qiao F, Petrásek J, Nick P - J. Exp. Bot. (2009)

Bottom Line: This synchrony can be inhibited by 1-N-naphthylphthalamic acid, an auxin transport inhibitor, and this process was accompanied by the disassembly of actin filaments.However, the synchrony could be rescued when the cells were cultured under white light or with exogenous indolyl-3-acetic acid.The rescue was most efficient for continuous far-red light followed by continuous blue light, whereas continuous red light was least effective.

View Article: PubMed Central - PubMed

Affiliation: Institute of Botany 1, University of Karlsruhe, Kaiserstrasse 2, Karlsruhe, Germany.

ABSTRACT
Pattern formation in plants has to cope with ambient variability and therefore must integrate environmental cues such as light. Synchrony of cell divisions was previously observed in cell files of tobacco suspension cultures, which represents a simple case of pattern formation. To develop cellular approaches for light-dependent patterning, light-responsive tobacco cell lines were screened from the cell line Nicotiana tabacum L. cv. Virginia Bright Italia 0 (VBI-0). The light responsive and auxin-autonomous cell line VBI-3 was isolated. As in the progenitor line VBI-0, cell divisions are synchronized in VBI-3 during exponential growth phase. This synchrony can be inhibited by 1-N-naphthylphthalamic acid, an auxin transport inhibitor, and this process was accompanied by the disassembly of actin filaments. However, the synchrony could be rescued when the cells were cultured under white light or with exogenous indolyl-3-acetic acid. The rescue was most efficient for continuous far-red light followed by continuous blue light, whereas continuous red light was least effective. These findings are discussed in the context of phytochrome-induced auxin biosynthesis and auxin-dependent synchrony of cell division.

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Cell division in VBI-3 follows a pattern that is independent of exogenous auxins. (A) Cell density of VBI-3 and VBI-0 over time after subcultivation. Density is given relative to the final value after 21 d of cultivation. (B) Morphology of VBI-3; bright-field and chlorophyll autofluorescence. (C) Frequency distribution over the number of cells per file in the initial state (day 0). (D) Frequency distribution during the logarithmic phase in the presence of exogenous auxins (control) or in the absence of NAA and 2,4-D for cultivation in the dark or under white light. The distributions are based on ≥400 (C) or ≥2000 (D) cell files from two independent experimental series. Error bars indicate the SE.
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fig1: Cell division in VBI-3 follows a pattern that is independent of exogenous auxins. (A) Cell density of VBI-3 and VBI-0 over time after subcultivation. Density is given relative to the final value after 21 d of cultivation. (B) Morphology of VBI-3; bright-field and chlorophyll autofluorescence. (C) Frequency distribution over the number of cells per file in the initial state (day 0). (D) Frequency distribution during the logarithmic phase in the presence of exogenous auxins (control) or in the absence of NAA and 2,4-D for cultivation in the dark or under white light. The distributions are based on ≥400 (C) or ≥2000 (D) cell files from two independent experimental series. Error bars indicate the SE.

Mentions: The tobacco cell line cv. Virginia Bright Italia 3 (VBI-3) has been derived from the tobacco cell line VBI-0 (Opatrný and Opatrná, 1976) as a clonal line selected for auxin-autonomous growth in continuous light. VBI-0 and VBI-3 are similar with respect to their life cycle, cell file axiality, and cell division synchrony (Fig. 1). The growth curves (Fig. 1A), plotted as cell density relative to the final cell density against time, are virtually identical for VBI-3 and VBI-0. As observed in the ancestral VBI-0, cell division in VBI-3 exhibits a clear axiality (Fig. 1B) and initiates from single cells and two-cell files (Fig. 1C) to generate pluricellular cell files. Frequency distributions constructed over the number of cells per file show higher frequencies of files with even cell numbers as compared with files with uneven cell numbers (Fig. 1D) as described for the ancestral line VBI-0 (Campanoni et al., 2003). However, in contrast to VBI-0, where cell division strictly requires exogenous NAA and 2,4-D (data not shown), cell division and synchrony in VBI-3 are independent of NAA and 2,4-D. In contrast to the ancestral VBI-0, VBI-3 forms chlorophyll-containing plastids when cultured under light conditions as detected by chlorophyll autofluorescence (Fig. 1B). However, the synchrony of cell division is not significantly altered when VBI-3 files cultivated in the dark are compared with those that have been cultivated under white light (Fig. 1D).


Light can rescue auxin-dependent synchrony of cell division in a tobacco cell line.

Qiao F, Petrásek J, Nick P - J. Exp. Bot. (2009)

Cell division in VBI-3 follows a pattern that is independent of exogenous auxins. (A) Cell density of VBI-3 and VBI-0 over time after subcultivation. Density is given relative to the final value after 21 d of cultivation. (B) Morphology of VBI-3; bright-field and chlorophyll autofluorescence. (C) Frequency distribution over the number of cells per file in the initial state (day 0). (D) Frequency distribution during the logarithmic phase in the presence of exogenous auxins (control) or in the absence of NAA and 2,4-D for cultivation in the dark or under white light. The distributions are based on ≥400 (C) or ≥2000 (D) cell files from two independent experimental series. Error bars indicate the SE.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2803214&req=5

fig1: Cell division in VBI-3 follows a pattern that is independent of exogenous auxins. (A) Cell density of VBI-3 and VBI-0 over time after subcultivation. Density is given relative to the final value after 21 d of cultivation. (B) Morphology of VBI-3; bright-field and chlorophyll autofluorescence. (C) Frequency distribution over the number of cells per file in the initial state (day 0). (D) Frequency distribution during the logarithmic phase in the presence of exogenous auxins (control) or in the absence of NAA and 2,4-D for cultivation in the dark or under white light. The distributions are based on ≥400 (C) or ≥2000 (D) cell files from two independent experimental series. Error bars indicate the SE.
Mentions: The tobacco cell line cv. Virginia Bright Italia 3 (VBI-3) has been derived from the tobacco cell line VBI-0 (Opatrný and Opatrná, 1976) as a clonal line selected for auxin-autonomous growth in continuous light. VBI-0 and VBI-3 are similar with respect to their life cycle, cell file axiality, and cell division synchrony (Fig. 1). The growth curves (Fig. 1A), plotted as cell density relative to the final cell density against time, are virtually identical for VBI-3 and VBI-0. As observed in the ancestral VBI-0, cell division in VBI-3 exhibits a clear axiality (Fig. 1B) and initiates from single cells and two-cell files (Fig. 1C) to generate pluricellular cell files. Frequency distributions constructed over the number of cells per file show higher frequencies of files with even cell numbers as compared with files with uneven cell numbers (Fig. 1D) as described for the ancestral line VBI-0 (Campanoni et al., 2003). However, in contrast to VBI-0, where cell division strictly requires exogenous NAA and 2,4-D (data not shown), cell division and synchrony in VBI-3 are independent of NAA and 2,4-D. In contrast to the ancestral VBI-0, VBI-3 forms chlorophyll-containing plastids when cultured under light conditions as detected by chlorophyll autofluorescence (Fig. 1B). However, the synchrony of cell division is not significantly altered when VBI-3 files cultivated in the dark are compared with those that have been cultivated under white light (Fig. 1D).

Bottom Line: This synchrony can be inhibited by 1-N-naphthylphthalamic acid, an auxin transport inhibitor, and this process was accompanied by the disassembly of actin filaments.However, the synchrony could be rescued when the cells were cultured under white light or with exogenous indolyl-3-acetic acid.The rescue was most efficient for continuous far-red light followed by continuous blue light, whereas continuous red light was least effective.

View Article: PubMed Central - PubMed

Affiliation: Institute of Botany 1, University of Karlsruhe, Kaiserstrasse 2, Karlsruhe, Germany.

ABSTRACT
Pattern formation in plants has to cope with ambient variability and therefore must integrate environmental cues such as light. Synchrony of cell divisions was previously observed in cell files of tobacco suspension cultures, which represents a simple case of pattern formation. To develop cellular approaches for light-dependent patterning, light-responsive tobacco cell lines were screened from the cell line Nicotiana tabacum L. cv. Virginia Bright Italia 0 (VBI-0). The light responsive and auxin-autonomous cell line VBI-3 was isolated. As in the progenitor line VBI-0, cell divisions are synchronized in VBI-3 during exponential growth phase. This synchrony can be inhibited by 1-N-naphthylphthalamic acid, an auxin transport inhibitor, and this process was accompanied by the disassembly of actin filaments. However, the synchrony could be rescued when the cells were cultured under white light or with exogenous indolyl-3-acetic acid. The rescue was most efficient for continuous far-red light followed by continuous blue light, whereas continuous red light was least effective. These findings are discussed in the context of phytochrome-induced auxin biosynthesis and auxin-dependent synchrony of cell division.

Show MeSH
Related in: MedlinePlus